The stratification of the lower ionosphere

Titheridge, J. E.

doi:10.1016/0021-9169(62)90098-3

Cited by 20 publications

(4 citation statements)

References 13 publications

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“…For example, Dieminger (1952), Gregory (1956Gregory ( , 1961, Titheridge (1962), Reid (1990), Jones et al (2004), and Hall et al (2006) discuss this for MF and HF, Bailey et al (1955) and Pineo (1956) for very high frequency (VHF; 30 to 300 MHz) forward scatter results, Bowles et al (1964) for both vertical and forward scatter VHF results, and Flock and Balsley (1967) for vertical incidence VHF results. At MF/HF, such preferred heights are subject to seasonal and annual variations, but persistent echoes occur from mean heights of about 65-68, 74-75, 83-85, and 92 km.…”

Section: Brief Historical Overviewmentioning

confidence: 99%

“…In more recent work, Bertoni et al (2013) briefly review some of these and suggest that a C layer of enhanced electron density does exist near 64 to 68 km for a few hours after dawn, but that its formation is associated with sunrise rather than with cosmic ray ionization. However, in the 50 to 110 km height region, the concept of a clear division between "E" and "D" regions and single "D" and "C" layers is slightly misleading, as the 50 to 100 km height region is stratified (e.g., Reid 1990), and most often consists of multiple regions of enhanced backscatter, with a tendency for this to occur at certain "preferred" heights for radar returns (e.g., Gregory 1961;Titheridge 1962;Reid 1990). This strong tendency to form layer-like regions of enhanced backscatter is overlaid with a strong diurnal variation in the heights of occurrence of radar returns.…”

Section: Introductionmentioning

confidence: 99%

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MF and HF radar techniques for investigating the dynamics and structure of the 50 to 110 km height region: a review

Reid

2015

Prog. in Earth and Planet. Sci.

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The application of medium-frequency (MF) and high-frequency (HF) partial reflection radar to investigate the neutral upper atmosphere is one of the oldest such techniques still regularly in use. The techniques have been continuously improved and remain a robust and reliable method of obtaining wind velocities, turbulence intensities, electron densities, and measurements of atmospheric structure in the mesosphere lower thermosphere (MLT) region (50 to 110 km). In this paper, we review recent developments, discuss the strengths and weaknesses of the technique, and consider possible improvements.

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Section: Brief Historical Overviewmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

MF and HF radar techniques for investigating the dynamics and structure of the 50 to 110 km height region: a review

Reid

2015

Prog. in Earth and Planet. Sci.

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“…A very confusing feature of the partial reflections observed by various workers [Gregory, 1961;Titheridge, 1962b]…”

Section: Ottawa But There Is No Doubt That the Electron Density At Tmentioning

confidence: 99%

Study of the lower ionosphere using partial reflection: 1. Experimental technique and method of analysis

Belrose¹,

Burke²

1964

J. Geophys. Res.

137

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The amplitude of weak echoes partially reflected from ionization irregularities in the height range 50-100 km are recorded. By utilizing two frequencies, 2.66 and 627 Mc/s, and recording the amplitudes of both the ordinary and extraordinary component waves, information is obtained about electron density and electron collision frequency in this height range under both normal and abnormal conditions. The method of analysis (discussed in detail in this paper) is essentially similar to that developed by Gardner and Pawsey, except that the generalized magnetoionic formulas, which take into account the energy dependence of the collision cross section, are employed. The results being obtained are believed to be more accurate in detail than those obtained by other ground-based techniques. Introduction. Our knowledge of electron densities and electron collision frequencies in the lower ionosphere (50-100 km) is relatively meager, partly because of observational limitations and partly because of difficulties in inter-preting the observational data that have been obtained. Under normal conditions the electron number densities are so low that low frequencies are needed for reflection in this height range. Despite an abundance of experimental data, few results have emerged from these studies. Under abnormal conditions the attenuation of radio waves propagating within the region can become so great that radio reflections, other than from the base of the ionosphere, are not obtained. The dynamic range of changes, even under normal conditions, is large, since the electron density and collision frequency change by about four orders of magnitude in the height range 50-100 km.The relatively high gas densities make environmental measurements with sounding rockets difficult, and most experiments have therefore been designed to provide information about the ionosphere at heights above 100 km. A few results have been obtained for the normal D region [Aikin et al., 1963; Kransnuskin and Kox With the University of Brisbane, Queensland, Australia (work performed while on sabbatical leave to DRTE during 1961). lesnikov, 1962], but these are less reliable than those obtained at times when radio-wave absorption was great [Kane, 1961; Jespersen et al., 1963].The magnitude of the electron density and its variation with height is roughly known, but superimposed on a general increase with height are important structural features, the dynamic changes of which cannot be studied by means of rockets. There is thus a need for a reliable means of studying the lower ionosphere by ground-based experiments. In recent years two new techniques have been developed for studying the D region. One of these, the ionospheric wave interaction experiment [Fejer, 1955; Barrington and Thrane, 1962] has given useful results, but there are major difficulties, both in the experimental technique and in the interpretation of the data. Another method utilizes the partial reflection of ordinary and extraordinary component waves from scatterers within the D region [Gardner ...

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“…tual height as seen at Narssarssuaq during 1958 and 1959. Titheridge [1962] analyzed some 4 X 10' echoes at 0.72 MHz at Cambridge, England, during two years near sunspot maximum. He concluded that although there were many reflections, they did not vary markedly with season or solar zenith angle.…”

mentioning

confidence: 99%

AnomalousD-region partial reflections after high-yield nuclear detonations

Stanley¹

1968

J. Geophys. Res.

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The stratification of the lower ionosphere

Cited by 20 publications

References 13 publications

MF and HF radar techniques for investigating the dynamics and structure of the 50 to 110 km height region: a review

MF and HF radar techniques for investigating the dynamics and structure of the 50 to 110 km height region: a review

Study of the lower ionosphere using partial reflection: 1. Experimental technique and method of analysis

AnomalousD-region partial reflections after high-yield nuclear detonations

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